Generally, sprinklers are installed in high buildings or structures having predetermined sizes or more so that in case of fire, it can be immediately extinguished. Such fire sprinklers are classified into a variety of types according to an installation method and the purpose of use. Depending on shapes, configurations, etc. of sprinkler heads, there may be a ceiling height limit, or a problem of malfunction may be caused.
FIG. 1 is a sectional view showing a sprinkler head according to a conventional technique. The sprinkler head of FIG. 1 is a fuse type sprinkler head using fusible metal.
The sprinkler head according to the conventional technique includes a frame 20, a fuse 50, a valve cap 30, and a deflector 40.
The frame 20 is coupled to a water supply pipe 10 which supplies water to the sprinkler head. The deflector 40 is coupled to a lower end of the frame 20 and functions to spray water supplied from a water outlet 21 of the frame 20 in all directions. A support 41 is coupled to an upper portion of the deflector 40. The valve cap 30 is installed to come into close contact with the water outlet 21 and close the water outlet 2, thus blocking supply water.
The fuse 50 presses the valve cap 30 onto the water outlet 21 so that the valve cap 30 can come into close contact with the water outlet 21 so as to openably close the water outlet 21. The fuse 50 is supported by the support 41. The force with which the fuse 50 presses the valve cap 30 can be adjusted by variation in height of the support 41. The fuse 50 includes a lever 51, an eccentric lever 52, and a fusible metal 53 which are installed to support the valve cap 30 in cooperation with each other. The eccentric lever 52 is disposed at an eccentric position displaced from an imaginary line connecting the support 41 and the center of the valve cap 30 with each other.
The operation of the sprinkler head according to the conventional technique will be described below. If fire occurs and the temperature of a room increases, the fusible metal 53 is exposed to high temperature. When the fusible metal 53 is heated to a predetermined temperature or more, the fusible metal 53 is melted. Then, balance between the levers 51 and 52 is lost. The levers 51 and 52 are thus separated from each other. Hence, the pressure that is applied to the valve cap 30 is removed. The valve cap 30 is therefore removed from the water outlet 21, whereby the water outlet 21 opens. Consequently, supply water is discharged out of the sprinkler head.
Typically, sprinkler heads are installed in buildings when the buildings are constructed, and then are semi-permanently used. With regard to the sprinkler head according to the conventional technique, while the levers 51 and 52 are exposed to high pressure of supply water over a long period of time, pressure is continuously applied from the levers 51 and 52 to the fusible metal 53. Thus, the fusible metal 53 may be deformed by the high pressure, and the levers 51 and 52 may be pushed into the fusible metal 53. In this case, the force with which the levers 51 and 52 support the valve cap 30 is reduced, whereby water leakage is caused.
Furthermore, because the eccentric lever is eccentrically disposed and is provided with a plurality of bent parts, the levers 51 and 52 may be easily bent by high pressure, thus causing a problem of water leakage or malfunction.
In addition, the structures of the levers 51 and 52 are complex. The fusible metal 53 and the levers 51 and 52 are separately provided from each other and must be assembled together in a fitting manner. Hence, it is difficult for the sprinkler head to be adapted to automated production.
Moreover, the fusible metal 53 comes into contact with only the edges of ends of the levers 51 and 52, so that a contact area therebetween is comparatively small. Thus, the rate at which heat is transferred to the fusible metal 53 is relatively low. Therefore, the conventional technique cannot be applied to a quick response sprinkler head which must have thermal responsiveness higher than that of a standard response sprinkler head.